Core recovery indicating device



Patented Sept. 15, 1953 Hal Haflolland; J r.,,6or y mesne assignmen pusChristig-Texaassignor, ts, to Standard: Oil Devel opment Company,Elizabeth, N. J., a, corporatlon'of Delaware Application July 14, 1952,Serial no, 298,781

8 Claims.

ingwhiol t:

Fig: L is an elevation, artly in section, showing an embodiment of thecore barrel in position in the drill stem for receiving a core;

Fig. 2- is an enlarged fragmentary View; partly in section; showingfurther details of constructiono! the embodiment of Fig; 1;

Fig; 2A is a view in section taken along the. line 2A-2A of Fig; 2; and,

Fig. 3 is an. enlarged fragmentary view similar to Fig. 2 showinganother embodiment of the present invention.

Turning now specifically to the drawing and first to Fig. I, aconventional drill bitA mounted in the lower end 015 drill stem B isshown in posi-' tion for cutting a core at the bottom of a borehole C'.

I e" principal parts of the core barrel shown -D with a packer tion ofbarrel D has moiznteet on its interior a vertically arranged seriesofstops K designated 5 6; 7 8, and 9 ofs rogressively decreasing diam--eterrin' the upward direction.

Cooperating with series of stops are dogs In the drawing the parts oflatch assembly F shown are clogs I 6 and retriev'ahl'e spear head'member [1. Since such latchesare WEIF known to the art, of constructionhave been omitted 111 order to a pluralitiy'oi'. spaced longitudinallyextending slots I 5.

2. Within the barrel D is mounted the circular ing a suitable recessinto which spring I3 is arranged to bias dogs i2 outwai'dly into contactwith. graduated stops KL Plate 20 is also provideo withslips 20a so asto allow only upward movement of assembly G.

25 having a central passage" with packing ring 26 which embraces andpacks off rod 22" of assembly GFa-t-a" point between piston Ll and lowerplate 20. Partition 2?, in elfect, divides core barrel D intoprogressively'decreasmgthe area of fiOW.- In the the annulus becorebarrel into the slots, it is desirable to provide a fluid passage fromthe part of the annulus above packer E to that part below packer E tofacilitate the withdrawal oi the core barrel assembly. In the embodimentof Figs. inasmuch as the packer E is mounted on the exterior of thebarrel and piston 2| makes contact with the interior of the barrel, thusthe thickness of the wall of barrel D allows slots IE to serve aspassages even if the upper end of plunger 2! is at the same level aspacker E. When piston 25 is raised so that its lower end is past thelower end of slots it an increased flow area is provided by passageways24 of piston 25 as will later be explained.

The two springs J and I3 are proportioned so that a change in theeffective length of J is suincient to cause a predetermined change inthe efiective length of l3. Thus, as spring J is cornpressed by core l8entering the barrel, the plunger assembly G moves upwardly compressingspring l3 and causing the dogs ii to move in turn past the stops I I.

In using the device of the present invention it may either be droppeddown the drill stem and then retrieved with a sand line after a core hasbeen cut or alternatively may be lowered on the end of a sand line. Inany event, it assumes the position shown in Fig. 1 when in core cuttingposition. The interior mechanism is initially arranged with plungerassembly G in a lower position with clogs ii in contact with thelowermost stop of the graduated stops l2. The interior of the barrel is,of course, free from a core so that circular plate H is in its lowermostposition and spring J is in its extended position. In the position ofplunger assembly G described, the upper wall of piston 2! is below thelower ends of longitudinal slots I5.

In cutting the core, the drill stem is rotated and drilling fluid ispumped downwardly through the drill stem in the usual manner. When thedrilling fluid reaches the point in the drill collar where the corebarrel assembly i arranged, it flows in the annular space between theouter wall of barrel D and the inner wall of drill stem 13 until itreaches packer E where it is forced to flow through slots into barrel D,then downwardly in the flow passage between the wall of barrel D and rod22, then outwardly through the lower portion of slots [5 and downwardlyin the annular space between the outer wall of barrel D and innersurface of drill stem B and then through the mud courses 10 of the drillbit. The mud then flows upwardly in the usual manner between the outerwall of drill stem D and the wall of borehole C.

As core 5% is cut it necessarily forces circular plate II upwardly inorder to enter the core barrel. This upward movement of plate H in turncauses spring J to compress. Since springs J and spring l3 are selectedto have a predetermined relationship, the compression of spring J acertain initial amount causes such a force to be exerted through plungerassembly G as to compress spring 13 and move it past stop 5, which isthe lowermost series of stops K. Upon movement of plunger assembly G,piston 2| of the assembly is forced upwardly until its upper end isabove the lower portion of longitudinal slot [5 thus reducing the amountof flow area for the drillin fluid and causing an indication at thesurface by an increase of pump pressure in the mud pumps. As additionalcore enters the barrel D, plate II is forced upwardly an additionalamount, in turn additionally compressing spring J and when thiscompression exceeds a predetermined amount the dogs 12 are pushed paststop 6, the second stop of the series of stops K, piston 2| movingupwardly and further reducing the flow area of slots l5 and causinganother increase of pump pressure.

The device as shown is proportioned such that as dogs l2 move upwardlyagainst stop members 5, 6, and 1 piston 2| progressively reduces theflow area of slots is thus causing three stepwise increases in mudpressure. However, in the embodiment shown, when the dogs I2 reach thisposition, the upper end of piston 2! has moved up even with the lowerend of packer E so that the pump pressure remains substantially constantwhile dogs I2 move along stop member a. Further upward movement ofpiston 21 (at which time dogs l2 are in contact with stop 9) causes thelower end of piston 2! to rise above the lower end of slot 15 and fluidmay flow through passages 24 of the piston and out through the exposedlower portions of slot l5 which will cause a reduction in pump pressure.Summarizing, the five stepwise movements along stops 5, 6, 1, 8, and 9result in three stepwise increases in pump pressure, then a step wherethe pump pressure remains constant and a. final step where the pumppressure decreases. When the pump pressure decreases or drops suddenly(the final step) this is an indication to the operator that the desiredamount of core is in the core barrel. At this point the lower end ofpiston 2! is above the lower ends of slots It, thus affording a bypassfor the flow of mud around cup packer E which allows the entire assemblyto be easily withdrawn.

It will be understood that if difilculty is encountered during thecoring operations so that core is not entering the barrel, the stepwiseincreases in mud pump pressure will not occur, and this will indicate tothe drilling crew that some correction of the coring operation should bemade. Thus, the device of the present invention enables a signal to betransmitted to the drilling crew at the surface at the time a core isbeing cut in the borehole so that it is unnecessary to withdraw the corebarrel in order to determine whether or not the attempt to take the coreis successful.

When the core barrel is to be removed from the drill stem, as when acore has been cut, it may be removed in the usual manner with a sandline.

As a further embodiment of the present invention, instead of a singleseries of longitudinal slots 15, two series of longitudinal slots, anupper series and a lower series, may be used. Such an embodiment isshown in a fragmentary View in Fig. 3. In Fig. 3 barrel D is providedwith an upper series of longitudinal slots 36 arranged above packer Eand a lower series of longitudinal slots 3i below packer E. Thisembodiment will operate in exactly the same way as in the embodiment ofFigs. l and 2 except that bypass passages are not provided adjacent cuppacker E for flow of fluid.

From the description of the present invention, it will be seen that Ihave provided a retrievable core barrel having a construction whichcauses stepwise changes in pressure in the mud pump as a core enters thecore barrel during the cutting of a core. Thus, the crew is providedwith a signal which indicates the success of the coring operation.

While I have disclosed specific embodiments of drill stem for thepassage. of drilling mud, said barrel having a partition to divide itinto a lower compartment fluidly sealed from an upper compartment andhaving alt-least one longitudinally extending slot in its wall abovesaid partition, re-- leasab'le latching means mounted on said barrel forlatching it to said drill stem, a packing mentber mounted on said barrelin such a way that at least aportion of said longitudinally extendingslot is exposed below said packing member, a longitudinally movableslide valve member mounted in the upper compartment in slidable sealingcontact with the inner wall of said barrel and arranged to be movedlongitudinally from a first position to a second position in which moreof the slot area below the packing member iscovered than in said firstposition, a contacting in the lower end of said barrel in the lowercompartment adapted to be forcausingsaid slide valve member to move fromits'first position to'its second position upon longitudinalm'oveinent ofsaid contacting member,

partition; a packing member mounted on said barrel in such a way that atleast aportion of said" longitudinally extending slot is exposed belowsaid packing member,

second pos tion in which more of the slot areal below the: packingmember is covered" than in said first position, a contactingmember'slidably fitting in the lower end. of said barrel. adapted to bepushed. upwardly asthe core enters said.

slide valve member to aocaaaa trail passage to divide 1 meat:

" :the upper compartment in slidinner wall of said moved longitudinallyupwardly as the core enters the barrel, a, rod passing? through: thecentral passage of said par.-

titi'on and mechanically linking said contacting partment from the lowercompartment.

4.. A core barrel for use in a drill stem adsaid barrel having a lowercompartment,

compartment adapted to be pushed upwardly as the core enters saidbarrel, a linkage mechanically connecting said contacting of saidcontacting member and carrying dogs arranged to make contact with saidseries of stops! and a. spring member. operatively arranged to bias saiddogs into contact with said stops.

5; A core" barrel for use in a drill stem adjain combination, an barreladapted to fit loosely in clearance between the outer surface of thebarrel and the inner surface of the passage of drilling mud, said barrelhaving apartition to divide it into a lower-compartment. fluidly sealedfrom an upper compartmentat least one longitudinally extending slot inits wall above said partition and a; longitudinally arranged series ofstopsof pro-- gressively differing diameter carried by the inner wall ofsaid barrel, releasable latching means mounted. on said barrel forlatching it to said drill stem, a packing member mounted on said barrelin such a way that at least a portion of said longitudinally extendingslot is exposed below said packing member, a longitudinally movableslide valve member mounted in the upper compartment in slidable sealingcontact with the inner wall of said barrel and arranged to be movedlongitudinally from a first position to a second position in which moreof the area of the slots below the packing member is covered than insaid first position, a contacting member slidably fitting in the lowerend of said barrel in the lower compartment adapted to be pushedupwardly as the core enters said barrel, a linkage mechanicallyconnecting said contacting member with said slide valve for causing saidslide valve member to move from its first position to its secondposition upon longitudinal movement of said contacting member andcarrying dogs arranged to make contact with said series of stops, afirst spring member operatively arranged to bias said dogs in contactwith said stops and a second spring member operatively arranged betweensaid contacting member and said plunger member, said first and secondspring members bearing such a relationship that a predetermined changein the efiective length of said second spring member causes apredetermined change in the effective length of the first spring memberwhereby a progressive upward movement of said contacting member causes apredetermined and smaller longitudinal movement of said plungerassembly.

6. A core barrel for use in a drill stem adjacent a drill bitcomprising, in combination, an elongated tubular barrel adapted to fitloosely in the drill stem with clearance between the outer surface ofthe barrel and the inner surface of the drill stem for the passage ofdrilling mud, said barrel having a partition pierced by a centralpassage to divide it into a lower compartment and an upper compartmentand having a plurality of circumferentially spaced longitudinallyextending slots in its'wall above said partition and a longitudinallyarranged series of stops of progressively differing diameter carried bythe inner wall of said barrel, releasable latching means mounted on saidbarrel for latching it to the drill stem, a packing member mounted onsaid barrel in such a way that at least a portion of each of saidlongitudinally extending slots are exposed below said packing member, acontacting member slidably fitting in the lower end of said barrel inthe lower compartment adapted to be pushed upwardly as the core enterssaid barrel, a plunger assembly mounted in said barrel for slidable1ongitudinal movement including a cylindrical slide valve member mountedin the upper compartment in slidable sealing contact with the inner wallof said barrel and arranged to be moved longitudinally from a firstposition to a second position in which more of the area of each of theslots below the packing member is covered than in said first position,and a rod passing through the central opening of the partition andextending into said lower compartment and having dogs mounted thereonarranged to make contact with said series of stops, a sealing membercarried by the partition making a fluid-tight seal with said rod portionof the plunger assembly for sealing the lower compartment fluidly fromthe upper compartment, a first spring member operatively arranged tobias said dogs into contact with said stops, a second spring memberoperatively arranged between said contacting member and said plungerassembly, said first and second spring members bearing such arelationship that a predetermined change in the effective length of thesecond spring member causes a predetermined change in the effectivelength of the first spring member whereby a progressive upward movementof said contacting member causes a predetermined and smallerlongitudinal movement of said plunger assembly.

'7. A core barrel for use in a drill stem adjacent a drill bitcomprising, in combination, an elongated tubular barrel adapted to fitloosely in the drill stem with clearance between the outer surface ofthe barrel and the inner surface of the drill stem for the passage ofdrilling mud, said barrel having at least one longitudinally extendingslot in its wall and a longitudinally arranged series of stops ofprogressively differ ing diameter carried by the inner wall of saidbarrel, releasable latching means mounted on said barrel for latching itto said drill stem, a packing member mounted on the slotted portion ofsaid barrel for making contact with the inner wall of said drill stemand of such dimensions that at least a portion of a longitudinallyextending slot extends above and at least a portion of a longitudinallyextending slot extends below said packing member, a contacting memberslidably fitting in the lower end of said barrel adapted to be pushedupwardly as the core enters said barrel, a plunger assembly mounted insaid barrel and including a valve member having a cylindricalimperforate wall in slidable sealing contact with the inner wall of saidbarrel and arranged to be moved longitudinally from a first position toa second position in which more of said slot area is covered than insaid first position, said plunger assembly having dogs arranged to makecontact with said series of stops, a first spring member operativelyarranged to bias said dogs into contact with said stops, a second springmember operatively arranged between said contacting member and saidplunger member, said first and second spring. members bearing such arelationship that a predetermined change in the effective length of thesecond spring member causes a predetermined change in the effectivelength of the first spring member whereby a progressive upward movementof said contacting member causes a predetermined and smallerlongitudinal movement of said plunger assembly.

8. A core barrel for use in a drill stem adjacent a drill bit,comprising in combination, an elongated tubular barrel adapted to fitloosely in the drill stem with clearance between the outer surface ofthe barrel and the inner surface of the drill stem for passage ofdrilling mud, said barrel having a partition pierced by a passage todivide it into a lower compartment and an upper compartment and havingat least one opening in its side wall above said partition, a packingmember mounted on said barrel in such a way that at least a portion ofsaid opening in the side wall is exposed below said packing member, amovable valve member mounted in the upper compartment in slidablesealing contact with the inner wall of said barrel and arranged to bemoved from a first position to a second position in which more of thearea of said position upon longitudinal movement of said opening in theside wall below the packing contacting member. member is covered than insaid first position, a HAL H. HOLLAND, JR.

end of said barrel in the lower compartment 5 References Cited in thefile of this patent adapted to be pushed upwardly as the core en- UNITEDSTATES PATENTS ters said barrel and a linkage mechanically con- Number ND t necting said contacting member with said slide 2,145,191 PenningtonJan. 24, 1939 valve member for causing said slide valve mem- 2,213,595Salnikov Sept. 3, 1940 her to move from its first position to its second10 2,613,918 Long Oct. 14, 1952

